A range of factors influence the health outcomes of an individual or the population. These include the interaction of socio-economic, biomedical and environmental factors which contribute to illness and injury. There are also specific lifestyle behaviours which may further impact a person's health, increasing the risk of chronic disease.

The 2004-05 NHS collected information on a number of self-reported lifestyle behaviours:

almost one in four adults (23%) smoked

13% of adults consumed alcohol at levels which, if continued, would be risky or a high risk to their health in the long term

70% of people aged 15 years and over reported sedentary or low exercise levels in the two weeks prior to interview

52% of people aged 15 years and over were classified as overweight or obese based on their calculated Body Mass Index where self-reported height and weight were known; this contrasts with only 33% who described themselves at interview as overweight

14% of people aged 12 years and over reported they usually consumed five or more serves of vegetables every day (the recommended daily intake)

54% of people aged 12 years and over reported they usually consumed two or more serves of fruit every day (the recommended daily intake).

Compared with the results of the 1995 NHS, the 2004-05 survey showed that more adults are drinking alcohol at risky or high risk levels (8% in 1995 and 13% in 2004-05) and more are overweight or obese (45% in 1995 and 53% in 2004-05), after adjusting for age differences. In contrast, there was no change over this time period in the proportion of adults reporting that they smoked (23%) or that they did no exercise or had exercised at a very low level (70%).